package util;
/*
 Porter stemmer in Java. The original paper is in
 Porter, 1980, An algorithm for suffix stripping, Program, Vol. 14,
 no. 3, pp 130-137,
 See also http://www.tartarus.org/~martin/PorterStemmer
 History:
 Release 1
 Bug 1 (reported by Gonzalo Parra 16/10/99) fixed as marked below.
 The words 'aed', 'eed', 'oed' leave k at 'a' for step 3, and b[k-1]
 is then out outside the bounds of b.
 Release 2
 Similarly,
 Bug 2 (reported by Steve Dyrdahl 22/2/00) fixed as marked below.
 'ion' by itself leaves j = -1 in the test for 'ion' in step 5, and
 b[j] is then outside the bounds of b.
 Release 3
 Considerably revised 4/9/00 in the light of many helpful suggestions
 from Brian Goetz of Quiotix Corporation (brian@quiotix.com).
 Release 4
 */
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
/**
 * Stemmer, implementing the Porter Stemming Algorithm.
 *
 * The Stemmer class transforms a word into its root form. The input
 * word can be provided a character at time (by calling add()), or at once
 * by calling one of the various stem(something) methods.
 */
public class EnglishStemmer {
	private char[] b;
	private int i, /* offset into b */
	i_end, /* offset to end of stemmed word */
	j, k;
	private static final int INC = 50;
	
	/* unit of size whereby b is increased */
	public EnglishStemmer()	{ 
		b = new char[INC];
		i = 0;
		i_end = 0;
	}
	
	/**
	 * Add a character to the word being stemmed. When you are finished
	 * adding characters, you can call stem(void) to stem the word.
	 */
	public void add(char ch) { 
		if (i == b.length) { //Resize the array 
			char[] new_b = new char[i+INC];
			for (int c = 0; c < i; c++) new_b[c] = b[c];
			b = new_b;
		}
		b[i++] = ch;
	}

	/** Adds wLen characters to the word being stemmed contained in a portion
	 * of a char[] array. This is like repeated calls of add(char ch), but
	 * faster.
	 */
	public void add(char[] w, int wLen) { 
		if (i+wLen >= b.length) { 
			char[] new_b = new char[i+wLen+INC];
			for (int c = 0; c < i; c++) new_b[c] = b[c];
			b = new_b;
		}
		for (int c = 0; c < wLen; c++) 
			b[i++] = w[c];
	}
	
	/**
	 * After a word has been stemmed, it can be retrieved by toString(),
	 * or a reference to the internal buffer can be retrieved by getResultBuffer
	 * and getResultLength (which is generally more efficient.)
	 */
	public String toString() { 
		return new String(b,0,i_end); 
	}

	/**
	 * Returns the length of the word resulting from the stemming process.
	 */
	public int getResultLength() { 
		return i_end; 
	}

	/**
	 * Returns a reference to a character buffer containing the results of
	 * the stemming process. You also need to consult getResultLength()
	 * to determine the length of the result.
	 */
	public char[] getResultBuffer() { 
		return b; 
	}

	/* cons(i) is true <=> b[i] is a consonant. */
	private final boolean cons(int i) { 
		switch (b[i]) {
		case 'a': case 'e': case 'i': case 'o': case 'u': return false;
		case 'y': return (i==0) ? true : !cons(i-1);
		default: return true;
		}
	}

	/* m() measures the number of consonant sequences between 0 and j. if c is
	 a consonant sequence and v a vowel sequence, and <..> indicates arbitrary
	 presence,
	 <c><v> gives 0
	 <c>vc<v> gives 1
	 <c>vcvc<v> gives 2
	 <c>vcvcvc<v> gives 3
	 ....
	 */
	private final int m() { 
		int n = 0;
		int i = 0;
		while(true) { 
			if (i > j) return n;
			if (! cons(i)) break; i++;
		}
		i++;
		while(true) { 
			while(true) { 
				if (i > j) return n;
				if (cons(i)) break;
				i++;
			}
			i++;
			n++;
			while(true) { 
				if (i > j) return n;
				if (! cons(i)) break;
				i++;
			}
			i++;
		}
	}
	
	/* vowelinstem() is true <=> 0,...j contains a vowel */
	private final boolean vowelinstem()	{ 
		int i; 
		for (i = 0; i <= j; i++) if (! cons(i)) 
			return true;
		return false;
	}

	/* doublec(j) is true <=> j,(j-1) contain a double consonant. */
	private final boolean doublec(int j) { 
		if (j < 1) return false;
		if (b[j] != b[j-1]) return false;
		return cons(j);
	}

	/* cvc(i) is true <=> i-2,i-1,i has the form consonant - vowel - consonant
	 and also if the second c is not w,x or y. this is used when trying to
	 restore an e at the end of a short word. e.g.
	 cav(e), lov(e), hop(e), crim(e), but
	 snow, box, tray.
	 */
	private final boolean cvc(int i) { 
		if (i < 2 || !cons(i) || cons(i-1) || !cons(i-2)) return false;
		{ int ch = b[i];
		if (ch == 'w' || ch == 'x' || ch == 'y') return false;
		}
		return true;
	}
	
	private final boolean ends(String s) { 
		int l = s.length();
		int o = k-l+1;
		if (o < 0) 
			return false;
		for (int i = 0; i < l; i++) if (b[o+i] != s.charAt(i)) 
			return false;
		j = k-l;
		return true;
	}

	/* setto(s) sets (j+1),...k to the characters in the string s, readjusting
	 k. */
	private final void setto(String s) { 
		int l = s.length();
		int o = j+1;
		for (int i = 0; i < l; i++) 
			b[o+i] = s.charAt(i);
		k = j+l;
	}

	/* r(s) is used further down. */
	private final void r(String s) { 
		if (m() > 0) setto(s); 
	}

	/* step1() gets rid of plurals and -ed or -ing. e.g.
	 caresses -> caress
	 ponies -> poni
	 ties -> ti
	 caress -> caress
	 cats -> cat
	 feed -> feed
	 agreed -> agree
	 disabled -> disable
	 matting -> mat
	 mating -> mate
	 meeting -> meet
	 milling -> mill
	 messing -> mess
	 meetings -> meet
	 */
	private final void step1() { 
		if (b[k] == 's') { 
			if (ends("sses")) k -= 2; 
			else
				if (ends("ies")) setto("i"); 
				else
					if (b[k-1] != 's') k--;
		}
		if (ends("eed")) { 
			if (m() > 0) k--; 
		} else
			if ((ends("ed") || ends("ing")) && vowelinstem()) { 
				k = j;
				if (ends("at")) setto("ate"); else
					if (ends("bl")) setto("ble"); else
						if (ends("iz")) setto("ize"); else
							if (doublec(k)) { 
								k--;
								{ 
									int ch = b[k];
									if (ch == 'l' || ch == 's' || ch == 'z') 
										k++;
								}
							}
							else if (m() == 1 && cvc(k)) setto("e");
			}
	}
	
	/* step2() turns terminal y to i when there is another vowel in the stem. */
	private final void step2() { 
		if (ends("y") && vowelinstem()) 
			b[k] = 'i'; 
	}

	/* step3() maps double suffices to single ones. so -ization ( = -ize plus
	 -ation) maps to -ize etc. note that the string before the suffix must give
	 m() > 0. */
	private final void step3() { 
		if (k == 0) return; /* For Bug 1 */ 
		switch (b[k-1])	{
		case 'a': 
			if (ends("ational")) { 
				r("ate"); 
				break; 
			}
			if (ends("tional")) { 
				r("tion"); 
				break; 
			}
			break;
		case 'c': 
			if (ends("enci")) { 
				r("ence"); 
				break; 
			}
			if (ends("anci")) { 
				r("ance"); 
				break; 
			}
			break;
		case 'e': 
			if (ends("izer")) { 
				r("ize"); 
				break; 
			}
			break;
		case 'l': 
			if (ends("bli")) { 
				r("ble"); break; 
			}
			if (ends("alli")) { 
				r("al"); 
				break; 
			}
			if (ends("entli")) { 
				r("ent"); 
				break; 
			}
			if (ends("eli")) { 
				r("e"); 
				break; 
			}
			if (ends("ousli")) { 
				r("ous"); 
				break; 
			}
			break;
		case 'o': 
			if (ends("ization")) { 
				r("ize"); 
				break; 
			}
			if (ends("ation")) { 
				r("ate"); 
				break; 
			}
			if (ends("ator")) { 
				r("ate"); 
				break; 
			}
			break;
		case 's': 
			if (ends("alism")) { 
				r("al"); 
				break; 
			}
			if (ends("iveness")) { 
				r("ive"); 
				break; 
			}
			if (ends("fulness")) { 
				r("ful"); 
				break; 
			}
			if (ends("ousness")) { 
				r("ous"); 
				break; 
			}
			break;
		case 't': 
			if (ends("aliti")) { 
				r("al"); 
				break; 
			}
			if (ends("iviti")) { 
				r("ive"); 
				break; 
			}
			if (ends("biliti")) { 
				r("ble"); 
				break; 
			}
			break;
		case 'g': 
			if (ends("logi")) { 
				r("log"); 
				break; 
			}
		} 
	}
	
	/* step4() deals with -ic-, -full, -ness etc. similar strategy to step3. */
	private final void step4() { 
		switch (b[k]) {
		case 'e': 
			if (ends("icate")) { 
				r("ic"); 
				break; 
			}
			if (ends("ative")) { 
				r(""); 
				break; 
			}
			if (ends("alize")) { 
				r("al"); 
				break; 
			}
			break;
		case 'i': 
			if (ends("iciti")) { 
				r("ic"); 
				break; 
			}
			break;
		case 'l': if (ends("ical")) { 
			r("ic"); 
			break; 
		}
		if (ends("ful")) { 
			r(""); 
			break; 
		}
		break;
		case 's': if (ends("ness")) { 
			r(""); 
			break; 
		}
		break;
		} 
	}
	
	/* step5() takes off -ant, -ence etc., in context <c>vcvc<v>. */
	private final void step5() { 
		if (k == 0) return; /* for Bug 1 */ 
		switch (b[k-1]) { 
		case 'a': 
			if (ends("al")) 
				break; 
			return;
		case 'c': 
			if (ends("ance")) 
				break;
			if (ends("ence")) 
				break; 
			return;
		case 'e': 
			if (ends("er")) 
				break; 
			return;
		case 'i': 
			if (ends("ic")) 
				break; 
			return;
		case 'l': 
			if (ends("able")) 
				break;
			if (ends("ible")) 
				break; 
			return;
		case 'n': 
			if (ends("ant")) 
				break;
			if (ends("ement")) 
				break;
			if (ends("ment")) 
				break;
			/* element etc. not stripped before the m */
			if (ends("ent")) 
				break; 
			return;
		case 'o': 
			if (ends("ion") && j >= 0 && (b[j] == 's' || b[j] == 't')) 
				break;
			/* j >= 0 fixes Bug 2 */
			if (ends("ou")) 
				break; 
			return;
			/* takes care of -ous */
		case 's': 
			if (ends("ism")) 
				break; 
			return;
		case 't': 
			if (ends("ate")) 
				break;
			if (ends("iti")) 
				break; 
			return;
		case 'u': 
			if (ends("ous")) 
				break; 
			return;
		case 'v': 
			if (ends("ive")) 
				break; 
			return;
		case 'z': 
			if (ends("ize")) 
				break; 
			return;
		default: 
			return;
		}
		if (m() > 1) 
			k = j;
	}
	
	/* step6() removes a final -e if m() > 1. */
	private final void step6() { 
		j = k;
		if (b[k] == 'e') { 
			int a = m();
			if (a > 1 || a == 1 && !cvc(k-1)) k--;
		}
		if (b[k] == 'l' && doublec(k) && m() > 1) k--;
	}

	/** Stem the word placed into the Stemmer buffer through calls to add().
	 * Returns true if the stemming process resulted in a word different
	 * from the input. You can retrieve the result with
	 * getResultLength()/getResultBuffer() or toString().
	 */
	public void stem() { 
		k = i - 1;
		if (k > 1) { 
			step1(); step2(); step3(); step4(); step5(); step6(); 
		}
		i_end = k+1; i = 0;
	}

	/** Test program for demonstrating the Stemmer. It reads text from a
	 * a list of files, stems each word, and writes the result to standard
	 * output. Note that the word stemmed is expected to be in lower case:
	 * forcing lower case must be done outside the Stemmer class.
	 * Usage: Stemmer file-name file-name ...
	 */
	public static void main(String[] args) {
		
		String path = "C:\\Documents and Settings\\ggb39\\jbproject\\documents for experiments";
		File file = new File(path);
		File files[] = file.listFiles();
		
		char[] w = new char[501];
		EnglishStemmer s = new EnglishStemmer();
		for (int i = 0; i < files.length; i++)
			try
			{
				FileInputStream in = new FileInputStream(path+"\\"+files[i].getName());
				try
				{ while(true)
				{ int ch = in.read();
				if (Character.isLetter((char) ch))
				{
					int j = 0;
					while(true)
					{ ch = Character.toLowerCase((char) ch);
					w[j] = (char) ch;
					if (j < 500) j++;
					ch = in.read();
					if (!Character.isLetter((char) ch)) {
						/* to test add(char ch) */
						for (int c = 0; c < j; c++) s.add(w[c]);
						/* or, to test add(char[] w, int j) */
						/* s.add(w, j); */
						s.stem();
						{
							String u;
							/* and now, to test toString() : */
							u = s.toString();
							/* to test getResultBuffer(), getResultLength() : */
							/* u = new String(s.getResultBuffer(), 0, s.getResultLength()); */
							System.out.print(u);
						}
						break;
					}
					}
				}
				if (ch < 0) break;
				System.out.print((char)ch);
				}
				}
				catch (IOException e)
				{ System.out.println("error reading " + files[i].getName());
				break;
				}
			}
		catch (FileNotFoundException e)
		{ System.out.println("file " + files[i].getName() + " not found");
		break;
		}
	}
}

